The Cretaceous Period lasted from around 141 to 65 million years ago. It saw the rise of flowering plants and diversification of many modern groups like insects and mammals. The period ended in a mass extinction, possibly caused by an asteroid impact, that wiped out non-avian dinosaurs and many marine reptiles. During the Cretaceous, the supercontinent Pangaea broke apart and climate became cooler with more pronounced seasons. Angiosperms and conifers dominated vegetation, though ferns were also common.
The document summarizes key aspects of the Mesozoic Era when dinosaurs ruled the Earth. It describes the three periods (Triassic, Jurassic, Cretaceous), the types of plants and animals that existed during this time, including early dinosaurs. It then focuses on the Cretaceous-Tertiary extinction event that wiped out the dinosaurs 66 million years ago, believed to have been caused by an asteroid impact. The impact would have caused global climate changes through atmospheric effects that disrupted ecosystems and food chains.
The document summarizes the geological time scale which divides Earth's history into eons, eras, periods, and epochs based on fossil and radiometric evidence. The four eons are the Hadean, Archean, Proterozoic, and current Phanerozoic eon which is divided into the Paleozoic, Mesozoic, and current Cenozoic era. Key periods include the Cambrian which saw an explosion of life, the Devonian which was the age of fishes, and the Mesozoic era in which reptiles dominated until the rise of mammals in the Cenozoic. The geological time scale provides a framework for understanding how life and the planet have evolved over
1. The document discusses the biodiversity and evolution of protists and animals, specifically focusing on cephalopods. It describes the key characteristics of cephalopods including their shells, bodies, senses, color changing abilities, and locomotion.
2. The reproduction processes of cephalopods are explained, involving internal fertilization and elaborate mating behaviors and color changes in some species.
3. Adaptive diversification of cephalopods is discussed, with the evolution of traits like chambered shells, advanced organ systems, and habitat/feeding adaptations leading to their diversity of forms.
This document provides information about the class Cephalopoda. It discusses key characteristics of cephalopods such as their highly developed sensory organs and efficient locomotion. It describes the major orders of cephalopods - Nautiloidea, Ammonoidea, and Coleoidea Dibranchia. For each order, it summarizes representative genera including their defining anatomical features and geological time periods. The document is an overview of cephalopod diversity and the use of ammonoids in particular as index fossils for dating rock layers.
This document provides information about the phylum Mollusca. It focuses on one class within this phylum, the Bivalvia (Lamellibranchia). Key points:
- Bivalvia are aquatic molluscs enclosed within a calcareous bivalve shell. They lack a head and have gills (lamellae) for respiration.
- The shell consists of two valves joined by a hinge, which are covered internally by the mantle. The mantle forms an enclosed mantle cavity.
- Three main types of dentition exist in the hinge: taxodont, with many small teeth; heterodont, with different sized teeth; and desmodont, replacing teeth with
This document summarizes coral reef biology and threats facing coral reef ecosystems. It describes the structure and formation of coral reefs, the requirements for coral growth, and different types of reefs. Corals reproduce both sexually and asexually. While coral reefs support significant biodiversity and provide economic value, they are threatened by overfishing, pollution, coastal development, climate change, and other human impacts. Protecting coral reefs through marine protected areas is important for conserving these fragile ecosystems.
The document summarizes the geologic time scale which divides Earth's history into sections including eons, eras, periods and epochs. The largest section is the eon, with the Precambrian and Phanerozoic eons covering over 4 billion years of history. Key events mentioned include the first life forms in the Archean era, marine invertebrates in the Proterozoic, and the rise of dinosaurs, mammals and modern life forms in the Phanerozoic. Several important periods are highlighted such as the Carboniferous, Permian, Jurassic and Cretaceous periods.
Trilobites were arthropods that lived from the Cambrian period to the end of the Permian period. They had a three-part body plan consisting of a head shield (cephalon), thorax, and tail shield (pygidium). Their exoskeleton allowed for morphological features like compound eyes, spines, and jointed limbs to be preserved as fossils. Trilobite morphology provides clues to their modes of life, including benthonic, pelagic, and infaunal habitats. Students are asked to diagram and analyze seven trilobite genera in relation to their adaptations for different lifestyles.
The document summarizes key aspects of the Mesozoic Era when dinosaurs ruled the Earth. It describes the three periods (Triassic, Jurassic, Cretaceous), the types of plants and animals that existed during this time, including early dinosaurs. It then focuses on the Cretaceous-Tertiary extinction event that wiped out the dinosaurs 66 million years ago, believed to have been caused by an asteroid impact. The impact would have caused global climate changes through atmospheric effects that disrupted ecosystems and food chains.
The document summarizes the geological time scale which divides Earth's history into eons, eras, periods, and epochs based on fossil and radiometric evidence. The four eons are the Hadean, Archean, Proterozoic, and current Phanerozoic eon which is divided into the Paleozoic, Mesozoic, and current Cenozoic era. Key periods include the Cambrian which saw an explosion of life, the Devonian which was the age of fishes, and the Mesozoic era in which reptiles dominated until the rise of mammals in the Cenozoic. The geological time scale provides a framework for understanding how life and the planet have evolved over
1. The document discusses the biodiversity and evolution of protists and animals, specifically focusing on cephalopods. It describes the key characteristics of cephalopods including their shells, bodies, senses, color changing abilities, and locomotion.
2. The reproduction processes of cephalopods are explained, involving internal fertilization and elaborate mating behaviors and color changes in some species.
3. Adaptive diversification of cephalopods is discussed, with the evolution of traits like chambered shells, advanced organ systems, and habitat/feeding adaptations leading to their diversity of forms.
This document provides information about the class Cephalopoda. It discusses key characteristics of cephalopods such as their highly developed sensory organs and efficient locomotion. It describes the major orders of cephalopods - Nautiloidea, Ammonoidea, and Coleoidea Dibranchia. For each order, it summarizes representative genera including their defining anatomical features and geological time periods. The document is an overview of cephalopod diversity and the use of ammonoids in particular as index fossils for dating rock layers.
This document provides information about the phylum Mollusca. It focuses on one class within this phylum, the Bivalvia (Lamellibranchia). Key points:
- Bivalvia are aquatic molluscs enclosed within a calcareous bivalve shell. They lack a head and have gills (lamellae) for respiration.
- The shell consists of two valves joined by a hinge, which are covered internally by the mantle. The mantle forms an enclosed mantle cavity.
- Three main types of dentition exist in the hinge: taxodont, with many small teeth; heterodont, with different sized teeth; and desmodont, replacing teeth with
This document summarizes coral reef biology and threats facing coral reef ecosystems. It describes the structure and formation of coral reefs, the requirements for coral growth, and different types of reefs. Corals reproduce both sexually and asexually. While coral reefs support significant biodiversity and provide economic value, they are threatened by overfishing, pollution, coastal development, climate change, and other human impacts. Protecting coral reefs through marine protected areas is important for conserving these fragile ecosystems.
The document summarizes the geologic time scale which divides Earth's history into sections including eons, eras, periods and epochs. The largest section is the eon, with the Precambrian and Phanerozoic eons covering over 4 billion years of history. Key events mentioned include the first life forms in the Archean era, marine invertebrates in the Proterozoic, and the rise of dinosaurs, mammals and modern life forms in the Phanerozoic. Several important periods are highlighted such as the Carboniferous, Permian, Jurassic and Cretaceous periods.
Trilobites were arthropods that lived from the Cambrian period to the end of the Permian period. They had a three-part body plan consisting of a head shield (cephalon), thorax, and tail shield (pygidium). Their exoskeleton allowed for morphological features like compound eyes, spines, and jointed limbs to be preserved as fossils. Trilobite morphology provides clues to their modes of life, including benthonic, pelagic, and infaunal habitats. Students are asked to diagram and analyze seven trilobite genera in relation to their adaptations for different lifestyles.
Phylum Echinodermata includes sea stars, sea cucumbers, brittle stars, sea urchins, and sand dollars. They are radially symmetrical with a pentamerous body plan and have a water vascular system and endoskeleton. The phylum contains four classes: Asteroidea (sea stars), Ophiuroidea (brittle stars), Echinoidea (sea urchins and sand dollars), and Holothuroidea (sea cucumbers). Echinoderms are found on the ocean floor and have tube feet, spines or plates, and can regenerate lost body parts. Their water vascular system is unique and used for movement, structure, and respiration.
The document summarizes the evolution of the horse over 50 million years from Eohippus to modern Equus. Key stages included Mesohippus which lived 38 million years ago in North America and had 3 toes, with the middle toe larger. Merychippus originated 12-6 million years ago and was the first single-toed horse with strong legs to increase speed and power. Pliohippus resembled a pony and lived in the late Miocene period in North America, being considered a direct link to modern Equus horses.
The document discusses the phylum Arthropoda, specifically the class Trilobita. Trilobites had a three-lobed body plan divided into three sections - the cephalon (head), thorax (body), and pygidium (tail). Their dorsal surface was protected by a calcareous exoskeleton. Trilobites first appeared in the Lower Cambrian period and became extinct by the end of the Paleozoic era. They exhibited changes over time including a reduction in thoracic segments and variations in eye and glabella morphology.
The document discusses invertebrate paleontology and provides information on fossils. It defines fossils and describes the types of fossils including body fossils (altered and unaltered remains) and trace fossils (tracks, trails, burrows, etc.). It explains the fossilization process and conditions required for preservation. It also discusses paleontology, evolution, the age of the earth, and types of paleontological studies including paleozoology, paleobotany, and micropaleontology.
The document summarizes the geological time scale which divides Earth's history into different eras, periods, and epochs based on fossil and stratigraphic evidence. It describes the four eons of Earth's history starting with the Hadean and Archean eons of the earliest lifeforms like bacteria. It then outlines the major eras - Paleozoic, Mesozoic, and Cenozoic - describing some of the significant lifeforms, events, and environmental changes that occurred during each period within these eras. The largest unit of the geological time scale is the eon, while the smallest is the epoch.
Fossils are remains or imprints of organisms that lived in the past. They can form in five ways: by being buried and preserved in sedimentary rock, trapped in amber, frozen in ice, replaced by minerals through petrification, or trapped in tar or asphalt. Fossils provide information to scientists about past organisms, environments, and how organisms have evolved over time. Certain index fossils are especially useful for determining the age of rock layers based on the period when that type of organism lived.
The document discusses Trilobites, an extinct group of arthropods that were abundant in the early Paleozoic era. It covers their general morphology, evolutionary trends over time, youngest fossil records in the Permian period, and geological distribution. Trilobites first appeared in the Cambrian period and went extinct in the Permian extinction event. They evolved from small creatures with simple features to larger forms with complex anatomies. Only five genera persisted until the end of the Permian period. Trilobites provide useful fossils for correlating strata between continents.
There are main 5 classes of living echinoderms:
crinoids (sea lilies and feather stars); asteroids (STARFISH); ophiuroids (brittle stars); echinoids (SEA URCHINS, etc); and holothuroids (sea cucumbers).
Echinoderms have been well preserved as FOSSILS; all existing classes and several others now extinct were present in the Ordovician (505-438 million years ago). They may have originated in the Precambrian (over 570 million years ago).
Common name : sea lilies, Sea Stars(STARFISH), sea urchins, sea cucumbers, and brittle stars.
Habitat
Echinoderms occupy all habitats including coral reefs, mangroves, seagrass and soft-bottom areas.
Except for a few species which inhabit brackish waters, all echinoderms are benthic organisms found in marine environments. Echinoderms inhabit depths ranging from shallow waters at tide lines to the deep sea.(Barnes, 1987; Brusca and Brusca, 2003; University of Alabama Center for Communication and Educational Technology, 2000; Waggoner, 1999)
Habitat Regions
• temperate
• tropical
• polar
• saltwater or marine
Aquatic Biomes
• brackish water
Other Habitat Features
• intertidal or littoral
GeoGraphy and eco-system
Geographic Range
Mainly a marine group, echinoderms are found in all the oceans. (Brusca and Brusca, 2003)
BIOGEOGRAPHIC REGIONS
• arctic ocean
• indian ocean
• atlantic ocean
• pacific ocean
• mediterranean sea
Eco-system
Sea urchins are among the main herbivores on reefs and there is usually a fine balance between the urchins and the kelp and other algae on which they graze. A diminution of the numbers of predators (otters, lobsters and fish) can result in an increase in urchin numbers causing overgrazing of kelp forests with the result that an alga-denuded "urchin barren" forms.
Work cited:
Lawrence, J. M. (1975). "On the relationships between marine plants and sea urchins". Oceanographic Marine Biological Annual Review 13: 213–286.
Ecosystem Roles
Echinoderms are usually intricate parts of their ecosystems. Many asteroids are keystone species. Sea urchins, if not controlled by predators, may overgraze their habitat. Asteroids have several commensals, including polychaetes that feed on leftovers from the sea star's prey items. (Barnes, 1987; Brusca and Brusca, 2003)
Ecosystem Impact: keystone species
This document discusses different types of fossils and fission track dating. It describes various ways that organisms can be preserved as fossils, including their entire bodies, original hard parts, skeletons, altered hard parts, and traces. Examples are given for each type like insects preserved in amber. Fission track dating is also summarized as a technique used to date uranium-bearing minerals based on analyzing damage trails left by radioactive decay. Rocks suitable for this method include apatite, zircon, and granite. The document outlines the process of fission track dating and its applications in understanding mountain belts, sediment provenance, and basin thermal evolution.
This document discusses the phylum Mollusca, class Gastropoda. It notes that gastropods include snails and slugs, with over 35,000 species. They are the largest and most varied class. The document then provides details on gastropod anatomy like their operculum and mantle, how they move, breathe and reproduce. It describes different gastropod species like terrestrial and sea slugs. It discusses defenses like cryptic coloration to avoid predation.
The document discusses methods used by scientists to study Earth's oceans. It describes how oceanography developed as a field in the late 1800s and 1920s using ships equipped with new measuring devices like sonar. Modern techniques like satellites and submersibles now map ocean surfaces, temperatures, currents, and seafloor features. Studies indicate Earth's early oceans formed from water released by volcanism that condensed as the planet cooled. Oceans now contain 97% of Earth's water and cover 71% of its surface.
The document discusses the K-T boundary problem, which marks the end of the Cretaceous period and the mass extinction event that wiped out the non-avian dinosaurs. The boundary is associated with the Chicxulub impact crater formed by an asteroid strike around 66 million years ago. Evidence suggests this impact triggered widespread environmental changes through effects like sulfur aerosols that blocked sunlight, causing a global climate shift and 75% of species to go extinct. Debate continues around other potential contributing factors like the Deccan Traps volcanic eruptions. The document provides details on the lithology, fossils, and occurrences of the K-T boundary in different regions including India.
1. The document traces the evolution of elephants from early proboscideans like Moeritherium and Phiomia to modern elephants.
2. Key changes during evolution included an increase in size, elongation of the nose and upper lip to form a trunk, development of tusks, and adaptation of teeth for a grazing diet.
3. Modern elephants belong to the genera Elephas and Loxodonta and are characterized by their huge size, pillar-like legs, trunk, and teeth adapted for grinding plant material.
SIGNIFICANCE OF CONODONTS IN MICROFOSSIL HISTORY Pramoda Raj
Conodonts are an extinct group of microscopic fossils that are significant in microfossil history. They are composed of calcium phosphate and resemble eel-like creatures. Conodonts first appeared in the Late Cambrian period and became extinct in the Late Triassic. They are useful for correlating strata and determining environmental factors like climate and water depth due to their abundance and wide geographic range during the Paleozoic era. Their tooth-like elements are prepared and studied using acid treatment and microscopy. Conodonts have been important for biostratigraphy and tracing evolutionary relationships.
The gastropods are an extremely diverse class of mollusks that includes snails and slugs. Most gastropods have a spiraling shell that surrounds their soft body and protects it. They have a well-defined head with ganglia but no ears, and excellent senses of smell and taste. Gastropods live on the seafloor in almost every marine environment and feed by scraping algae and decaying matter off surfaces using a rasping tongue called a radula. They reproduce through external fertilization and development.
The document summarizes the Geologic Time Scale which divides Earth's history into units including eons, eras, periods, and epochs. It describes the three main eras:
1) The Paleozoic Era (544-251 million years ago) which was dominated by invertebrates and saw the rise of fish and amphibians on land and sea.
2) The Mesozoic Era (251-65 million years ago) which was dominated by reptiles like dinosaurs and saw the rise of mammals and the breakup of Pangaea.
3) The ongoing Cenozoic Era (past 65 million years) which is the "Age of Mammals" and
The document summarizes the geologic time scale which divides Earth's history into sections called eons, eras, periods, and epochs based on major changes. It describes several important periods including the Precambrian, Paleozoic, Mesozoic, and Cenozoic eras. The Paleozoic era saw the first appearance of hard-shelled animals and plants colonizing land. It ended in a mass extinction event. The Mesozoic era was dominated by reptiles such as dinosaurs, until another mass extinction wiped them out. The current Cenozoic era is when mammals and eventually humans evolved.
Dinosaurs dominated land for over 160 million years. Birds evolved from small feathered theropod dinosaurs and are now considered a type of dinosaur. While sauropods like Brachiosaurus were the largest at over 30 meters long, small feathered dinosaurs like Microraptor were only around a chicken's size. Dinosaurs displayed a diversity of body shapes, sizes, diets and behaviors during their long reign.
The Cretaceous Period lasted from 144 to 65 million years ago. It saw the rise of flowering plants and the end of the dinosaurs. During this period, the continents continued to drift apart from the single landmass of Pangea. New groups of mammals, birds, and insects appeared while dinosaurs like T-Rex and Triceratops dominated on land. In the oceans, marine reptiles like plesiosaurs and mosasaurs were abundant. By the end of the Cretaceous, a mass extinction wiped out the dinosaurs and many other species.
The document discusses key facts about the Cretaceous Period including that it was the last period of the dinosaurs, named for "chalk", and the youngest period of the Mesozoic Era. Specific dinosaurs covered include Tyrannosaurus Rex, Triceratops, Velociraptor, as well as brief facts about each.
Phylum Echinodermata includes sea stars, sea cucumbers, brittle stars, sea urchins, and sand dollars. They are radially symmetrical with a pentamerous body plan and have a water vascular system and endoskeleton. The phylum contains four classes: Asteroidea (sea stars), Ophiuroidea (brittle stars), Echinoidea (sea urchins and sand dollars), and Holothuroidea (sea cucumbers). Echinoderms are found on the ocean floor and have tube feet, spines or plates, and can regenerate lost body parts. Their water vascular system is unique and used for movement, structure, and respiration.
The document summarizes the evolution of the horse over 50 million years from Eohippus to modern Equus. Key stages included Mesohippus which lived 38 million years ago in North America and had 3 toes, with the middle toe larger. Merychippus originated 12-6 million years ago and was the first single-toed horse with strong legs to increase speed and power. Pliohippus resembled a pony and lived in the late Miocene period in North America, being considered a direct link to modern Equus horses.
The document discusses the phylum Arthropoda, specifically the class Trilobita. Trilobites had a three-lobed body plan divided into three sections - the cephalon (head), thorax (body), and pygidium (tail). Their dorsal surface was protected by a calcareous exoskeleton. Trilobites first appeared in the Lower Cambrian period and became extinct by the end of the Paleozoic era. They exhibited changes over time including a reduction in thoracic segments and variations in eye and glabella morphology.
The document discusses invertebrate paleontology and provides information on fossils. It defines fossils and describes the types of fossils including body fossils (altered and unaltered remains) and trace fossils (tracks, trails, burrows, etc.). It explains the fossilization process and conditions required for preservation. It also discusses paleontology, evolution, the age of the earth, and types of paleontological studies including paleozoology, paleobotany, and micropaleontology.
The document summarizes the geological time scale which divides Earth's history into different eras, periods, and epochs based on fossil and stratigraphic evidence. It describes the four eons of Earth's history starting with the Hadean and Archean eons of the earliest lifeforms like bacteria. It then outlines the major eras - Paleozoic, Mesozoic, and Cenozoic - describing some of the significant lifeforms, events, and environmental changes that occurred during each period within these eras. The largest unit of the geological time scale is the eon, while the smallest is the epoch.
Fossils are remains or imprints of organisms that lived in the past. They can form in five ways: by being buried and preserved in sedimentary rock, trapped in amber, frozen in ice, replaced by minerals through petrification, or trapped in tar or asphalt. Fossils provide information to scientists about past organisms, environments, and how organisms have evolved over time. Certain index fossils are especially useful for determining the age of rock layers based on the period when that type of organism lived.
The document discusses Trilobites, an extinct group of arthropods that were abundant in the early Paleozoic era. It covers their general morphology, evolutionary trends over time, youngest fossil records in the Permian period, and geological distribution. Trilobites first appeared in the Cambrian period and went extinct in the Permian extinction event. They evolved from small creatures with simple features to larger forms with complex anatomies. Only five genera persisted until the end of the Permian period. Trilobites provide useful fossils for correlating strata between continents.
There are main 5 classes of living echinoderms:
crinoids (sea lilies and feather stars); asteroids (STARFISH); ophiuroids (brittle stars); echinoids (SEA URCHINS, etc); and holothuroids (sea cucumbers).
Echinoderms have been well preserved as FOSSILS; all existing classes and several others now extinct were present in the Ordovician (505-438 million years ago). They may have originated in the Precambrian (over 570 million years ago).
Common name : sea lilies, Sea Stars(STARFISH), sea urchins, sea cucumbers, and brittle stars.
Habitat
Echinoderms occupy all habitats including coral reefs, mangroves, seagrass and soft-bottom areas.
Except for a few species which inhabit brackish waters, all echinoderms are benthic organisms found in marine environments. Echinoderms inhabit depths ranging from shallow waters at tide lines to the deep sea.(Barnes, 1987; Brusca and Brusca, 2003; University of Alabama Center for Communication and Educational Technology, 2000; Waggoner, 1999)
Habitat Regions
• temperate
• tropical
• polar
• saltwater or marine
Aquatic Biomes
• brackish water
Other Habitat Features
• intertidal or littoral
GeoGraphy and eco-system
Geographic Range
Mainly a marine group, echinoderms are found in all the oceans. (Brusca and Brusca, 2003)
BIOGEOGRAPHIC REGIONS
• arctic ocean
• indian ocean
• atlantic ocean
• pacific ocean
• mediterranean sea
Eco-system
Sea urchins are among the main herbivores on reefs and there is usually a fine balance between the urchins and the kelp and other algae on which they graze. A diminution of the numbers of predators (otters, lobsters and fish) can result in an increase in urchin numbers causing overgrazing of kelp forests with the result that an alga-denuded "urchin barren" forms.
Work cited:
Lawrence, J. M. (1975). "On the relationships between marine plants and sea urchins". Oceanographic Marine Biological Annual Review 13: 213–286.
Ecosystem Roles
Echinoderms are usually intricate parts of their ecosystems. Many asteroids are keystone species. Sea urchins, if not controlled by predators, may overgraze their habitat. Asteroids have several commensals, including polychaetes that feed on leftovers from the sea star's prey items. (Barnes, 1987; Brusca and Brusca, 2003)
Ecosystem Impact: keystone species
This document discusses different types of fossils and fission track dating. It describes various ways that organisms can be preserved as fossils, including their entire bodies, original hard parts, skeletons, altered hard parts, and traces. Examples are given for each type like insects preserved in amber. Fission track dating is also summarized as a technique used to date uranium-bearing minerals based on analyzing damage trails left by radioactive decay. Rocks suitable for this method include apatite, zircon, and granite. The document outlines the process of fission track dating and its applications in understanding mountain belts, sediment provenance, and basin thermal evolution.
This document discusses the phylum Mollusca, class Gastropoda. It notes that gastropods include snails and slugs, with over 35,000 species. They are the largest and most varied class. The document then provides details on gastropod anatomy like their operculum and mantle, how they move, breathe and reproduce. It describes different gastropod species like terrestrial and sea slugs. It discusses defenses like cryptic coloration to avoid predation.
The document discusses methods used by scientists to study Earth's oceans. It describes how oceanography developed as a field in the late 1800s and 1920s using ships equipped with new measuring devices like sonar. Modern techniques like satellites and submersibles now map ocean surfaces, temperatures, currents, and seafloor features. Studies indicate Earth's early oceans formed from water released by volcanism that condensed as the planet cooled. Oceans now contain 97% of Earth's water and cover 71% of its surface.
The document discusses the K-T boundary problem, which marks the end of the Cretaceous period and the mass extinction event that wiped out the non-avian dinosaurs. The boundary is associated with the Chicxulub impact crater formed by an asteroid strike around 66 million years ago. Evidence suggests this impact triggered widespread environmental changes through effects like sulfur aerosols that blocked sunlight, causing a global climate shift and 75% of species to go extinct. Debate continues around other potential contributing factors like the Deccan Traps volcanic eruptions. The document provides details on the lithology, fossils, and occurrences of the K-T boundary in different regions including India.
1. The document traces the evolution of elephants from early proboscideans like Moeritherium and Phiomia to modern elephants.
2. Key changes during evolution included an increase in size, elongation of the nose and upper lip to form a trunk, development of tusks, and adaptation of teeth for a grazing diet.
3. Modern elephants belong to the genera Elephas and Loxodonta and are characterized by their huge size, pillar-like legs, trunk, and teeth adapted for grinding plant material.
SIGNIFICANCE OF CONODONTS IN MICROFOSSIL HISTORY Pramoda Raj
Conodonts are an extinct group of microscopic fossils that are significant in microfossil history. They are composed of calcium phosphate and resemble eel-like creatures. Conodonts first appeared in the Late Cambrian period and became extinct in the Late Triassic. They are useful for correlating strata and determining environmental factors like climate and water depth due to their abundance and wide geographic range during the Paleozoic era. Their tooth-like elements are prepared and studied using acid treatment and microscopy. Conodonts have been important for biostratigraphy and tracing evolutionary relationships.
The gastropods are an extremely diverse class of mollusks that includes snails and slugs. Most gastropods have a spiraling shell that surrounds their soft body and protects it. They have a well-defined head with ganglia but no ears, and excellent senses of smell and taste. Gastropods live on the seafloor in almost every marine environment and feed by scraping algae and decaying matter off surfaces using a rasping tongue called a radula. They reproduce through external fertilization and development.
The document summarizes the Geologic Time Scale which divides Earth's history into units including eons, eras, periods, and epochs. It describes the three main eras:
1) The Paleozoic Era (544-251 million years ago) which was dominated by invertebrates and saw the rise of fish and amphibians on land and sea.
2) The Mesozoic Era (251-65 million years ago) which was dominated by reptiles like dinosaurs and saw the rise of mammals and the breakup of Pangaea.
3) The ongoing Cenozoic Era (past 65 million years) which is the "Age of Mammals" and
The document summarizes the geologic time scale which divides Earth's history into sections called eons, eras, periods, and epochs based on major changes. It describes several important periods including the Precambrian, Paleozoic, Mesozoic, and Cenozoic eras. The Paleozoic era saw the first appearance of hard-shelled animals and plants colonizing land. It ended in a mass extinction event. The Mesozoic era was dominated by reptiles such as dinosaurs, until another mass extinction wiped them out. The current Cenozoic era is when mammals and eventually humans evolved.
Dinosaurs dominated land for over 160 million years. Birds evolved from small feathered theropod dinosaurs and are now considered a type of dinosaur. While sauropods like Brachiosaurus were the largest at over 30 meters long, small feathered dinosaurs like Microraptor were only around a chicken's size. Dinosaurs displayed a diversity of body shapes, sizes, diets and behaviors during their long reign.
The Cretaceous Period lasted from 144 to 65 million years ago. It saw the rise of flowering plants and the end of the dinosaurs. During this period, the continents continued to drift apart from the single landmass of Pangea. New groups of mammals, birds, and insects appeared while dinosaurs like T-Rex and Triceratops dominated on land. In the oceans, marine reptiles like plesiosaurs and mosasaurs were abundant. By the end of the Cretaceous, a mass extinction wiped out the dinosaurs and many other species.
The document discusses key facts about the Cretaceous Period including that it was the last period of the dinosaurs, named for "chalk", and the youngest period of the Mesozoic Era. Specific dinosaurs covered include Tyrannosaurus Rex, Triceratops, Velociraptor, as well as brief facts about each.
- The Miocene Epoch lasted from approximately 23 million to 5 million years ago. During this time, grazing animals became more common after the rise of grasses. Both grazers and their predators evolved to be faster to maneuver on the grassy plains.
- A severe drought in the region killed thousands of animals, whose bones were later discovered preserved in river bends after being swept downstream.
- The document discusses the Miocene Epoch in further detail, including the climate and geography at the time as well as notable animals and events.
The document summarizes key events in Earth's history from the formation of the solar system to the present. It describes the origin of life beginning with simple prokaryotes over 3 billion years ago. The first complex eukaryotic cells emerged around 1.7 billion years ago, followed by multicellular organisms over 700 million years ago. The development of land plants and animals is outlined through the Precambrian, Paleozoic, Mesozoic and Cenozoic eras, along with changing climates and configurations of the Earth's continents and oceans. Absolute and relative dating methods are also summarized that are used to determine the age of geological features and fossils.
MINERAL RESOURCE AND RESERVE DECLARATIONS AND ASSET MANAGEMENT; Resource Evaluation; Mineral Resource Asset Management; Inferred Mineral Resources; Indicated Mineral Resources; Measured Mineral Resources; Mineral reserves; Reserve definition; Feasibility study; GEOLOGIC CONDITIONS AND CHARACTERISTIC OF ORE DEPOSITS; MINE GEOLOGY RESPONSIBILITIES; Geological Database Configuration; Ore Control Process
MINE LIFE CYCLE; LIFE CYCLE OF DEPOSITS; LIFE-CYCLE OF A MINE PROJECT; STAGES IN THE LIFE CYCLE OF A MINE PROJECT; Prospecting; Exploration ; 3D modeling software's for mining sectors; Mineral Resource; Mineral Reserve; Development; Exploitation ; MINE PLANNING CYCLE ; Reclamation; ENVIRONMENTAL IMPACTS OF NONRENEWABLE MINERAL RESOURCES; SOURCES OF METAL POLLUTION; Harmful Environmental Effects of Mining; Persistent, Bio-accumulative and Toxi (PBT ); Lead; Mercury; Cadmium; Arsenic
Limestone;Industrial Uses of Limestone ; Lime; Lime Cycle; Production of Lime; Classification of Hydrated Lime IS 712-1973; Purposes for the Utilize of Lime; Soda Ash;Solvay process for the manufacture of Soda Ash; Purposes for the Utilize of Soda Ash; Gypsum; Calcination of Gypsum; Hardening of Plaster; Magnesium; Production Of Magnesium from seawater and dolomite; Process for production Magnesium hydroxide and Calcium chloride from Dolomite ; Process for production Magnesium and Calcium chloride
This document discusses processing sand and silica sand into other materials. It begins by outlining examples of mineral processing including sand, silica sand, and heavy mineral sand. For processing sand and silica sand, it describes extracting, washing, classifying, and removing impurities from the sand through steps like screening, attrition scrubbing, hydrocyclones, and magnetic separation. The sand can then be further processed into silicon, silicon carbide, and silicone through reducing silica to ferrosilicon, purifying it through distillation of trichlorosilane, and using the Siemens process to deposit high purity silicon. Heavy mineral sands can also be separated into minerals like zircon, rut
This document provides an outline for a lecture series on mining geology. It introduces key concepts related to mining, including definitions of mining, minerals, and ore deposits. It discusses various types of ore deposits and characteristics that determine their economic viability, such as grade, shape, depth, and stability. The document also lists topics that will be covered in each lecture, including ore mineralogy, the mining cycle, resource classification, mining methods, processing, waste management, and environmental issues. The series aims to give students a non-technical overview of the mining and mineral extraction process.
zeolites, types, nature, synthetic, processes, Deposits and properties;Physical characteristics of some naturally occurring zeolites; molecular sieves;Adsorption and related molecular sieving; zeolite catalysts
Open pit mining involves digging a large hole or pit at the earth's surface to extract ore deposits near the surface. Overburden or waste rock is removed to expose the ore body, which is then extracted using large excavating equipment like shovels and haul trucks. Ore is transported from the pit either by truck or conveyor belt to a processing facility. Open pit mining provides high productivity and low costs but requires significant capital investment and can have large environmental impacts due to the large scale of surface disturbance. It is best suited to deposits that are relatively shallow and large in area.
The document discusses underground mining methods. It begins by explaining that the choice of mining method depends on characteristics of the orebody like thickness and dip, as well as the competency of surrounding rock. It then provides details on various hard rock and soft rock underground mining methods. These include longwall mining, room-and-pillar, blast mining, shortwall mining, and coal skimming for soft rocks. For hard rocks, methods include various stoping techniques, longwall mining, and caving methods. Stoping is defined as the process of extracting ore by leaving behind an open space called a stope.
The document discusses the Devonian period and various Devonian fossil sites. It begins by explaining the etymology of the term "Devonian" from Devon, England where the rocks were first studied. It then describes three specific Devonian fossil sites - a fossil gorge in Iowa discovered after flooding where crinoids, brachiopods and coral can be found, fossil beds in Indiana and Kentucky originally part of the Ohio River featuring rugosan corals, brachiopods and trilobites, and formations in Oklahoma containing over 30 trilobite species.
The benthic zone is located at the bottom of the oceans and is very cold, dark, and high-pressure due to the lack of sunlight penetration. Organisms that live in the benthic zone have adaptations like bioluminescence to find food and fast swimming to evade predators in the difficult conditions without light and under high pressure.
The Devonian Period lasted from 417 to 354 million years ago. During this time, temperatures fluctuated and primitive plant life emerged on land. The early Devonian saw warm temperatures and simple plant life less than 3 feet tall. Middle Devonian temperatures cooled in some regions as plant life became more diverse. Late Devonian temperatures increased again and forests of trees up to 30 feet tall developed. Several extinction events occurred near the end of the period, including the Hangenberg Event, which caused the demise of some marine life groups. By the late Devonian, the continents had largely merged into a single landmass called Pangaea through the process of plate tectonics.
The Jurassic period occurred around 150-200 million years ago. It was home to many iconic dinosaurs like the Archaeopteryx, Dilophosaurus, Brachiosaurus, and Stegosaurus. The Archaeopteryx was an early bird that lived in Germany and may have been able to fly or glide. The Dilophosaurus was a speedy carnivore that lived in Arizona. The huge herbivorous Brachiosaurus lived in Colorado and Tanzania. Finally, the armored Stegosaurus inhabited Wyoming and Utah. The Jurassic period eventually ended, making way for the Cretaceous period.
The Mesozoic Era lasted from about 250 to 65 million years ago. It is known as the Age of Dinosaurs, as non-avian dinosaurs dominated terrestrial landscapes. The era saw the breakup of the supercontinent Pangaea into smaller continents and dramatic climate changes from dry conditions in the Triassic to warmer, more humid periods in the Jurassic and Cretaceous. Life diversified during this time, though many species went extinct at the end of the era when an asteroid impact wiped out the dinosaurs and many other forms of life.
The document discusses 5 major mass extinctions that have occurred in Earth's history. Mass extinctions refer to the extinction of a large number of species within a short period of time across the globe. The biggest mass extinction was the Permian-Triassic extinction about 252 million years ago, which killed off around 95% of all species. Causes of mass extinctions included climate change, asteroid impacts, volcanic eruptions, and changes in sea levels. The 6th mass extinction is currently underway due to human activity such as pollution, habitat destruction, and overexploitation of resources. Up to 50% of all species may go extinct by 2100 if human impacts are not addressed.
Geological time scale- Haeden to Recentsruthy sajeev
The document provides an overview of the geological time scale, which divides Earth's history into eons, eras, periods, and epochs based on fossil evidence. The Paleozoic era saw the evolution of early life, including fish, amphibians, and reptiles. It ended with the largest mass extinction, the Permian-Triassic extinction. The Mesozoic era that followed was dominated by reptiles such as dinosaurs. It included the Triassic, Jurassic, and Cretaceous periods and ended with the Cretaceous-Paleogene extinction.
1. The document outlines the major periods in the geologic history of Earth from the Precambrian Eon to the present Cenozoic Era. It describes the major life forms, events, and changes that occurred during each period.
2. The periods are organized into larger divisions of geologic time including eons, eras, and periods. The Precambrian saw the earliest life forms evolve. The Paleozoic saw the Cambrian explosion of life and the rise of fish and land plants.
3. Mass extinctions occurred between periods, including the end-Permian mass extinction which wiped out 95% of marine species. The Mesozoic saw the rise of dinosaurs and mammals. It
The document summarizes the major geological time periods from the Hadean Eon to the present Holocene Epoch. It describes key environmental conditions and evolutionary developments that occurred during each period. The Hadean saw the formation of Earth's early hot molten surface. Life first emerged in the Archean Eon as simple single-celled organisms. Oxygen began accumulating in the Proterozoic with the rise of photosynthetic bacteria. Complex multicellular life evolved during the Cambrian explosion, which began the Phanerozoic Eon of visible life. Mammals became dominant in the Cenozoic after the K-T extinction wiped out the dinosaurs. The Holocene covers modern human history over
This document provides an overview of geologic history from the Precambrian era to present day. It describes the major eras, periods, events, climate changes, organisms, and theories of evolution that are recorded in the layers of rock and fossil records. The document is organized chronologically, with each era and period summarized in terms of dominant life forms, environmental conditions, and significant developments or extinctions. Major theories like plate tectonics and mass extinction events are also outlined.
The document provides a timeline of major geological eras and periods from the formation of Earth 4.6 billion years ago to present day. It describes how scientists divided Earth's history into a geological time scale based on studying rock layers and fossils. The eons, eras, periods and epochs are outlined, with key events noted such as the first life in the Archean Era, mass extinctions in the Permian and Cretaceous periods, and the rise of mammals and humans in the Cenozoic Era. Major periods like the Carboniferous, Jurassic, and Quaternary are highlighted for their significance.
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardized international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective[1] is to precisely define global chronostratigraphic units of the International Chronostratigraphic Chart (ICC)[2] that are used to define divisions of geologic time. The chronostratigraphic divisions are in turn used to define geochronologic units.[2]
While some regional terms are still in use,[3] the table of geologic time presented in this article conforms to the nomenclature, ages, and color codes set forth by the ICS as this is the standard, reference global geologic time scale – the International Geological Time Scale.[1][
The document provides information about the Cambrian Period, which began around 543 million years ago and ended around 490 million years ago. It describes the Cambrian Period as a time of the "Cambrian Explosion" when most major animal phyla first appeared in the fossil record over a relatively short period of time. The document outlines the dominant life forms, climate, tectonic setting, stratigraphy, localities, and subdivisions of the Cambrian Period.
The document discusses five major mass extinction events that have occurred throughout Earth's history. It provides details on the timing, affected organisms, and hypothesized causes for each extinction. The largest was the Permian-Triassic extinction 252 million years ago, in which over 96% of marine species and 70% of terrestrial vertebrates died off, possibly due to one or more factors including asteroid impact, volcanism, and climate change. Subsequent extinctions discussed are the Ordovician-Silurian, Late Devonian, Triassic-Jurassic, and Cretaceous-Tertiary events. Each had significant impacts on biodiversity and the dominant lifeforms on Earth.
- The first geologic time scale was proposed in 1913 by British geologist Arthur Holmes, estimating Earth's age at around 4 billion years old, much older than previously believed.
- Geologists have divided Earth's history into time intervals of varying lengths marked by significant geological or biological events, such as mass extinctions.
- The time scale includes eons like the Phanerozoic Eon which are hundreds of millions of years long and divided into eras like the Cenozoic, Mesozoic and Paleozoic marked by very significant events. Eras are further divided into periods which are also defined by boundary events.
1) The document discusses the geological time scale which is used to divide Earth's history into standardized units including eras, periods, and epochs.
2) Scientists have studied rocks and fossils worldwide to develop the time scale and determine how life has changed over time on Earth.
3) Major events in Earth's history like asteroid impacts have caused mass extinctions and influenced the conditions and diversity of life.
The document discusses the Geological Time Scale which is used to divide Earth's history into eras, periods and epochs based on fossil and rock evidence. It describes the major eras - Precambrian, Paleozoic, Mesozoic and Cenozoic - along with key environmental conditions and lifeforms that existed during each era, noting major extinction events. The timeline shows how life on Earth has evolved and changed dramatically over its approximately 4.5 billion year history.
The document summarizes the geologic time scale which divides Earth's history into eons, eras, periods, and epochs based on fossil evidence. Major developments include the Cambrian explosion of life 540 million years ago, the rise of dinosaurs in the Mesozoic era, and the dominance of mammals including early humans in the Cenozoic era following the extinction of dinosaurs.
The document provides an overview of the geologic time scale by describing the major eons, eras, periods, and epochs that have occurred throughout Earth's history from 4.6 billion years ago to present day. It notes key events such as the formation of the early Earth and oceans during the Hadean and Archean eons, the emergence of early life forms in the Precambrian eon, the explosion of animal diversity in the Cambrian period, the rise of reptiles and dinosaurs in the Mesozoic era, and the extinction of dinosaurs paving the way for mammals in the Cenozoic era. The summary covers Earth's geologic and biological progression from its formation to the current era.
The Paleozoic Era lasted from 543 to 248 million years ago. It was divided into seven periods: Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, and Permian. Major events included the diversification of multi-celled animal life in the Cambrian and a mass extinction at the end of the Paleozoic that wiped out 90% of marine species. Life colonized land during this era, with plants, fungi and insects moving ashore.
The document summarizes the geological time scale which divides Earth's history into different eras, periods, and epochs based on fossil and stratigraphic evidence. It describes the four eons of Earth's history starting with the Hadean and Archean eons of the earliest lifeforms like bacteria. It then outlines the major eras - Paleozoic, Mesozoic, and Cenozoic - describing some of the significant lifeforms, events, and environmental changes that occurred during each period within these eras. The largest unit of the geological time scale is the eon, while the smallest is the epoch.
History of the Earth - How our World Came to BeVinay Parikh
The document provides an overview of the major geological time periods from the Hadean Eon to the Cretaceous Period. It summarizes the defining features and key events of each period such as the formation of oceans, evolution of early life, dominance of certain species, mass extinctions, movement of tectonic plates, and climate changes. The time periods discussed include the Hadean, Archean, Proterozoic, Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, and Cretaceous.
The objectives of this course in iron ore Resources and iron industry are:
i) acquainting students (majors and non-majors) with the basic tools necessary for studying iron ore deposits and processes,
ii) different processes for phosphorus removal from iron ore
iii) beneficiation processes of iron ore deposits.
iv) different processes and techniques that used to enrichment low-grade iron ore resources
v) understanding the different ironwork processes and technology,
vi) understanding the different types of iron ore products,
vii) prominent routes for steelmaking
viii) understanding the relationship between the distribution of iron ore and scrap, as well as steelmarkets,
ix) steel industry in Egypt , and
x) gaining some knowledge of the global iron ore as well as environmental problems associated with the extraction and utilization of iron ore resources.
There are plenty of hard-to-beneficiate iron ores and high-grade tailings in India and all over the world; As the volume of high-grade iron ores declines.
Minerals phase transformation by hydrogen reduction (MPTH) can efficiently revitalize hard-to-beneficiate iron ore resources and tailings, turning the waste into profitable products. It may also improve the concentrate quality comparing to that from the previous method. From the economic and environmental aspects, MPTH is the most effective method to recover iron oxides.
The clean minerals phase transformation by hydrogen reduction (MPTH) was proposed.
Industrial utilization of limonite/goethite, limonite-hematite, sulfur-bearing refractory iron ore was achieved, where Sulfur-bearing minerals decomposed or formed sulfate after oxidation roasting.
Sulfur content of iron ore concentrate was significantly reduced to 0.038 %.
Improving utilization efficiency of refractory iron ore resources is a common theme for the sustainable development of the world’s steel and iron industry.
Magnetization Roasting is considered as an effective and typical method for the beneficiation of refractory iron ores.
After magnetization roasting, the weakly magnetic iron minerals, including hematite, limonite and siderite, are selectively reduced or oxidized to ferromagnetic magnetite, which is relatively easier to enrich by Magnetic Separation after liberation pretreatments.
The Primary Magnetization Roasting Methods include: Shaft Furnace Roasting, Rotary Kiln Roasting, Fluidized Bed Roasting, and Microwave assisted roasting. The developments in magnetization roasting of difficult to treat iron ores, including: Shaft Furnace Roasting, Rotary Kiln Roasting, Fluidized Bed Roasting, and Microwave Assisted Roasting in the Past Decade.
Shaft Furnace Roasting is gradually eliminated due to its high energy consumption and low industrial processing capacity, and the primary problem for rotary kiln roasting is the kiln coating which affects the yield of iron resource and its industrial application.
Fluidized Bed Roasting and Microwave assisted roasting are considered as the most effective and promising methods.
Suspension (Fluidized) Magnetization Roasting is recognized as the most effective and promising technology due to its high reaction efficiency, low energy consumption and large processing capacity. Moreover, an industrial production line with a throughput of 1.65 million t/a for beneficiation of a specularite ore has been built.
Microwave Assisted Roasting is a potential alternative technology for magnetizing iron ores. However, it is currently limited to laboratory research and has no industrial application. Forwarding microwave assisted magnetization roasting methods into industrial applications needs long way and time to achieve.
Furthermore, using biomass, H2 or siderite as a reducing agent in the magnetic reduction roasting of iron ores is a beneficial way to reduce carbon emissions, which can be called clean and green magnetization roasting technology.
In the future, technical research on clean and green magnetization roasting should be strengthened. Maybe microwave magnetization roasting using biomass/H2/siderite as reductant can be further studied for a more effective and greener magnetization of iron ores.
WORLD RESOURCES IRON DEPOSITS
Iron Ore Pellets Market Industry Trends
Scope and Market Size
Market Analysis and Insights
DRI Production in Plants Using Merchant Iron Ore
Outlook for DR grade pellet supply‐demand out to 2030
DRI and the pathway to carbon‐neutral steelmaking
Supply‐side challenges for the steel & iron ore industries
scrap is the main raw material, is growing in the structure of global steelmaking capacities; SCARP/ RECYCLING IRON ; EAF steel production method in the world; Scrap for Stock; A Global Scrap Shortage;Availability of Ferrous Scrap Resources; EGYPT IRON SCRAP IMPORTS.
The iron ore production has significantly expanded in recent years, owing to increasing steel demands in developing countries.
However, the content of iron in ore deposits has deteriorated and low-grade iron ore has been processed.
The fine ores resulting from the concentration process must be agglomerated for use in iron and steelmaking.
Bentonite is the most used binder due to favorable mechanical and metallurgical pellet properties, but it contains impurities especially silica and alumina.
Better quality wet, dry, preheated, and fired pellets can be produced with combined binders, such as organic and inorganic salts, when compared with bentonite-bonded pellets.
While organic binders provide sufficient wet and dry pellet strengths, inorganic salts provide the required preheated and fired pellet strengths.
The industrial development program of any country, by and large, is based on its natural resources.
Currently the majority of the world’s steel is produced through either one of the two main routes: i) the integrated Blast Furnace – Basic Oxygen Furnace (BF – BOF) route or ii) the Direct Reduced Iron - Electric Arc Furnace (DRI - EAF) route.
Depleting resources of coking coal, the world over, is posing a threat to the conventional (Blast Furnace [Bf]–Basic Oxygen Furnace [BOF]) route of iron and steelmaking.
During the last four decades, a new route of ironmaking has rapidly developed for Direct Reduction (DR) of iron ore to metallic iron by using noncoking coal/natural gas.
This product is known as Direct Reduced Iron (DRI) or Sponge Iron.
Processes that produce iron by reduction of iron ore (in solid state) below the melting point are generally classified as DR processes.
Based on the types of reductant used, DR processes can be broadly classified into two groups: (1) coal-based DR process and (2) gas-based DR process.
Details of DR processes, reoxidation, storage, transportation, and application of DRI are discussed in this presentation.
This presentation reviews the different DR processes used to produce Direct Reduced Iron (DRI), providing an analysis on the quality requirements of iron-bearing ores for use in these processes. The presentation also discusses the environmental sustainability of such processes. DR processes reduce iron ore in its solid state by the use of either natural gas or coal as reducing agents, and they have a comparative advantage of low capital costs, low emissions and production flexibility over the BF process.
Currently the majority of the world’s steel is produced through either one of the two main routes: i) the integrated Blast Furnace – Basic Oxygen Furnace (BF – BOF) route or ii) the Direct Reduced Iron - Electric Arc Furnace (DRI - EAF) route.
In the former, the blast furnace uses iron ore, scrap metal, coke and pulverized coal as raw materials to produce hot metal for conversion in the BOF. Although it is still the prevalent process, blast furnace hot metal production has declined over the years due to diminishing quality of metallurgical coke, low supply of scrap metal and environmental problems associated with the process. These factors have contributed to the development of alternative technologies of ironmaking, of which Direct Reduction (DR) processes are expected to emerge as preferred alternatives in the future.
This presentation reviews the different DR processes used to produce Direct Reduced Iron (DRI), providing an analysis on the quality requirements of iron-bearing ores for use in these processes. The presentation also discusses the environmental sustainability of such processes. DR processes reduce iron ore in its solid state by the use of either natural gas or coal as reducing agents, and they have a comparative advantage of low capital costs, low emissions and production flexibility over the BF process.
Ironmaking represents the first step in steelmaking.
The iron and steel industry is the most energy-intensive and capital-intensive manufacturing sector in the world (Strezov, 2006).
Steelmaking processes depend on different forms of iron as primary feed material. Traditionally, the main sources of iron for making steel were Blast Furnace hot metal and recycled steel in the form of scrap.
The Blast Furnace (BF) has remained the workhorse of worldwide virgin iron production (i.e., hot metal) for more than 200 years. Over the years, BFs have evolved into highly efficient chemical reactors, capable of providing stable operation with a wide range of feed materials.
However, operation of modern efficient BFs normally involves sintering and coke making and their associated environmental problems.
More than 90% of iron is currently produced via the BF process, while the rest is coming from Direct Reduction (DR) processes, Mini Blast Furnaces (MBFs), Corex, Finex, Ausmelt, etc. Additionally, the severe shortage of good-quality metallurgical coal has remained an additional constraint all over the world. In view of this, there is an increasing awareness that the BF route needs to be supplemented with alternative ironmaking processes that are more environment friendly and less dependent on metallurgical coal.
The document discusses reduction roasting followed by magnetic separation as a promising technique for enriching iron values from low-grade iron ores. It provides an overview of the technique, noting that reduction roasting involves reducing hematite and goethite phases in iron ores to magnetite, which can then be separated magnetically. The document reviews reduction roasting studies on various types of low-grade iron ores, including oolitic iron ores, banded iron ores, iron ore slimes and tailings. Emerging trends in reduction roasting such as microwave-assisted and biomass-assisted methods are also examined.
Phosphorus removal from iron ore is important for efficient steelmaking. Various processes have been developed to reduce phosphorus levels prior to smelting, including physical separation techniques that leverage differences in particle properties, and chemical/hydrometallurgical methods utilizing reagents to selectively remove or transform phosphorus. Further optimization is needed to improve phosphorus removal efficiency and minimize environmental impacts.
Overview of IRON TYPES: Pig Iron, Direct Reduced Iron (DRI), Hot Briquetted Iron (HBI), Cold Briquetted Iron (CBI) and Cold Briquetted Iron and Carbon (CBIC) Specifications .
Comparison of Pig Iron and DRI
Properties; Manufacturing Process; Uses; Largest producers and markets
Iron ore mining plays a critical role in supplying the raw material necessary for steel production, supporting various industries and economic development worldwide.
From the extraction of iron ore to its processing and eventual export, each stage of the mining process requires careful planning, technological advancements, and environmental considerations.
By adopting sustainable mining practices and mitigating environmental impacts, the future of iron ore mining can be aligned with the principles of responsible resource utilization and environmental stewardship
The Egyptian steel sector is the second largest steel market in the Middle East and North Africa region in terms of production and third largest in terms of consumption.
Egypt was the third-ranked producer of Direct-Reduced Iron (DRI) in the Middle east and North Africa region after Iran and Saudi Arabia and accounted for 5.4% of the world’s total output
The Egyptian steel industry represents one of the cornerstones of Egypt’s economic growth and development, due to its linkages to almost all other industries that stimulate economic expansion, such as construction, housing, infrastructure, consumer goods and automotive. All these industries rely heavily on steel industry and so, the importance and development of the steel sector is significant for the progress of the Egyptian economy in general.
The Egyptian market has many companies that produce different steel products.
This document provides the curriculum vitae of Prof. Dr. Hassan Zakaria Harraz. It details his personal and academic background, including his education, positions held, research interests, and publications. He is currently a professor of economic geology and ore resources at Tanta University in Egypt. The CV outlines his extensive experience in economic geology, mineral exploration, and research focused on gold deposits in Egypt. It also lists over 30 of his published papers on related topics.
Exploration in Deep Weathering Profiles, Supergene, R-mode factor analysis; Multi-element association geochemistry; Assessment of Au-Zn potentiality in Gossan; Rodruin-Egypt
Mineral Processing: Crusher and Crushing; Secondary and Tertiary Crushing Circuits; Types of Crusher; Types of Crushing; Types of Jaw Crushers; Impact Crusher; Types of Cone Crushers; Ball Mill; BEST STONE MANUFACTURERS; Local Quality and High quality ; International and Country/Hand made
Classification Equipment
Introduction; Chemical composition of garnet; Structure; Classification; Physical properties; Optical properties; Occurrences; Gem variety; and Uses
Garnet group of minerals is one of the important group of minerals.
Since they are found in wide variety of colours, they are also used as gemstones.
Garnet group of minerals are also abrasives and thus have various industrial applications.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
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PPT on Direct Seeded Rice presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
Basics of crystallography, crystal systems, classes and different forms
Cretaceous Periods
1. • The Cretaceous Period (meaning "chalk," from the many chalk deposits of
this age [the White Cliffs of Dover, to name one]) easily stands as one of the
most popular times among the general populus. The period extends from
about 141 million years ago until 65 million years ago.
• Duration :71 million years
• The name Cretaceous was derived from chalk (Crai, Kreides, Latin Creta)
known in England, France, Germany. This chalk is a facies which changed
laterally into sandstone in other places on the border of the Cretaceous
basin in Europe.
• It show a wider extension than in the Jurassic.
• It is found in most of the Europian countries, North Africa, Egypy, Arabia,
Turkey
• The Cretaceous was also punctuated and concluded by one of the greatest
mass extinctions of all time. About half of all animal families did not make
the transition to the Tertiary Period.
Facies:
• They exhibit considerable local variation, generally:
The Lower Cretaceous formations are all non-marine being
of terrestrial and estuarine origin, the lower member begins with
basal sands that are coarse and gravelly, commonly arkose and
generally cross –bedded. Sands and clays alternate and also grade
laterally on into another.
The Upper Cretaceous beds rest unconformably upon the lower
2. Astroblemes
• Eleven major impact structures are known
from the Cretaceous, but none rival the
terminal event in Cretaceous existence.
Some 65 million years ago a massive
asteroid, 10-20 km in diameter struck the
Earth north of the Yucatan Peninsula in
what is now the Gulf of Mexico. The
resulting crater approaches 300 km in
diameter, and is the second-largest
craterform structure known.
• The asteroid would have been travelling at a
speed between 10 and 20 km per second
when it entered Earth's atmosphere and a
relatively oblique angle from the south.
• Both the air and any water would have
provided negligible resistance, and the
resulting impact with the Earth's surface
would have kicked up billions of
3. • tons of substrate. The dust
entered the atmosphere,
presumably blocking out sunlight
for an extended time (perhaps 6
months).
• Models suggest that a global
cooling would have resulted for
about 10 years due to a 10-20%
reduction in solar transmission
through the atmosphere. This, in
turn, would be followed by a
warming trend for about 100
years due to a greenhouse effect
4. Special Events
Rise of the Rocky Mountains
• During the Cretaceous, severe compressional forces were
in play throughout Idaho, Wyoming, and Utah, causing
masses of rock to be moved horizontally and folded
upward. During the Middle Cretaceous, this uplift was
further aided by plutonic and volcanic action on the West
Coast.
Mass Extinction
• The close of the Cretaceous also marks a time of mass
extinction, certainly in part due to impact by an
extraterrestrial body. This was the second-greatest
extinction of all time, with about half of all animal families
not making the transition to the Paleocene.
• All of the dinosaurs became extinct, and marine reptiles
and flying pterosaurs vanished as well. Among the
invertebrates, the ammonoids and belemnoids were wiped
out, and many families of clams and snails were
eliminated. Corals lost two-thirds of their members.
• A few groups, such as land plants, mammals, fishes,
brachiopods, and amphibians, lost relatively few
representatives.
11. The Cretaceous Period 144 to 65 Million Years
Ago
• The Cretaceous is usually noted for being the last portion
of the "Age of Dinosaurs", but that does not mean that new
kinds of dinosaurs did not appear then.
• It is during the Cretaceous that the first ceratopsian and
pachycepalosaurid dinosaurs appeared. Also during this
time, we find the first fossils of many insect groups,
modern mammal and bird groups, and the first flowering
plants.
• The breakup of the world-continent Pangaea, which began
to disperse during the Jurassic, continued. This led to
increased regional differences in floras and faunas
between the northern and southern continents.
• The end of the Cretaceous brought the end of many
previously successful and diverse groups of organisms,
such as non-avian dinosaurs and ammonites. This laid open
the stage for those groups which had previously taken
secondary roles to come to the forefront. The Cretaceous
was thus the time in which life as it now exists on Earth
came together.
12. Subdivisions of the Cretaceous:
The chart at left shows the major
subdivisions of the Cretaceous Period. The
Coniacian Age is not labelled here, because
it is too short to allow this -- you will notice
it as a narrow strip between the Santonian
and Turonian.
This chart is mapped, to allow you to travel
back to the Jurassic, or forward into the
Paleogene (in the Cenozoic Era). The
Cretaceous Period is part of the
Mesozoic Era
.
- Maastrichtian
- Campanian
- Santonian
- Coniacian = Late Cretaceous
- Turonian
- Cenomanian
--------------------------
- Albine
- Aptian =Early Cretaceous
- Barremian
- Neocomain
---------------------
Subdivisions of the Cretaceous:
13. Cretaceous Period: Stratigraphy
Subdivisions of the
Cretaceous:
The chart at left shows the major
subdivisions of the Cretaceous
Period. The Coniacian Age is not
labelled here, because it is too short
to allow this -- you will notice it as a
narrow strip between the Santonian
and Turonian.
This chart is mapped, to allow you to
travel back to the Jurassic, or
forward into the Paleogene (in the
Cenozoic Era).
The Cretaceous Period is part of the
Mesozoic Era.
14.
15. Cretaceous Period: Life
• No great extinction or burst of diversity separated the Cretaceous from the
Jurassic Period that had preceded it.
• In some ways, things went on as they had. Dinosaurs both great and small
moved through forests of ferns, cycads, and conifers.
• Ammonites, belemnites, other molluscs, and fish were hunted by great
"marine reptiles," and pterosaurs and birds flapped and soared in the air
above. Yet the Cretaceous saw the first appearance of many lifeforms that
would go on to play key roles in the coming Cenozoic world.
• Perhaps the most important of these events, at least for terrestrial life, was
the first appearance of the flowering plants, also called the angiosperms or
Anthophyta.
• appearing in the Lower Cretaceous around 125 million years ago, the
flowering plants first radiated in the middle Cretaceous, about 100 million
years ago. By the close of the Cretaceous, a number of forms had evolved
that any modern botanist would recognize.
• At about the same time, many modern groups of insects were beginning to
diversify, and we find the oldest known ants and butterflies. Aphids,
grasshoppers, and gall wasps appear in the Cretaceous, as well as termites
and ants in the later part of this period. Another important insect to evolve
was the eusocial bee, which was integral to the ecology and evolution of
flowering plants.
• The Cretaceous also saw the first radiation of the diatoms in the oceans
(freshwater diatoms did not appear until the Miocene).
Life of the Cretaceous
Flora
Ficus stavina
:Fauna
16. Life of the Cretaceous
Many of the Jurassic genera still exist in the Cretaceous together with the
apprearance of new forms. Sudden disappearance of most of the
characteristic Cretaceous genera
before coming of the Eocene ones.
Flora: Ferns, Cycads and Coniferse are still the most important tribs of
vegetation.
Cycads were exceedingly developed and widely spread and the
Mesozoic sometimes called the, age of Cycads .
Development and spead of Angiosperms (true flowering plant). Calcareous
Nannoplankton( Nannofossils)
Fauna
Foraminifera: exceedingly abundant as rock builders of chalk and other
calcareous rocks.
Corals and Sponges: locally abundant, reef builders developed in few
localities.Solitary corals e.g. Cyclolites were soread widely.
Echinoderms: Crinoids do not play important part as in the
Jurassic.Echinoides very
important e.g. Cidris, Cassidulus, Hemiaster.
Brachiopods : shown gradual declination, numerous only in restricted
regions.
Pelecypods and Gastropods:abundant of many kinds and essentially of moden
appearance e.g. Oysters, Exogyra….etc.Rudists were distinctive builders of bioherms and
associated with acteonillids.
Cephalopods: mainly Ammonites and Belemnites both were on a decline
numerically although the Ammonites still played a
conspicuous role until the end of the period.
26. Cretaceous Period: Localities
• Cretaceous localities on this
server: (see map above)
• Clayton Lake, New Mexico - One of
the most extensive and best
preserved dinosaur trackways in
the United States is this
Cretaceous site.
• Hell Creek, Montana
• Pt. Loma Formation - This
California locality has yielded
inportant fossils for understanding
western North American dinosaurs
• Cretaceous in
Egypt
• The Cretaceous rocks
covers about 2/5 of
Egypt's surface.
• In Sinai
• Gebel Shabraweat
• Gebel Ataqa and along the
Red Sea Coast
27. Cretaceous: Tectonics and Paleoclimate
• The Cretaceous is defined as the period between 144 and 65 million years ago, the last
period of the Mesozoic Era, following the Jurassic and ending with the extinction of the
dinosaurs. By the beginning of the Cretaceous, the supercontinent Pangea was already
rifting apart, and by the mid-Cretaceous, it had split into several smaller continents.
This crested large-scale geographic isolation, causing a divergence in evolution of all
land-based life for the two new land masses.
• The rifting apart also generated extensive new coastlines, and a corresponding increase
in the available near-shore habitat. Additionally, seasons began to grow more
pronounced as the global climate became cooler. Forests evolved to look similar to
present day forests, with oaks, hickories, and magnolias becoming common in North
America by the end of the Cretaceous.
• At the end of the Cretaceous period, 65 million years ago, an asteroid hit Earth in the
Yucatán Peninsula, Mexico, forming what is today called the Chicxulub impact crater.
It has been estimated that half of the world's species went extinct at about this time, but
no accurate species count exists for all groups of organisms. Some have argued that
many of the species to go extinct did so before the impact, perhaps because of
environmental changes occuring at this time. Whatever its cause, this extinction event
marks the end of the Cretaceous and of the Mesozoic Era
28. • The appearance and diversification of angiosperms characterizes this period. Flowering plants
invaded more varied environments and created a niche for themselves in the damper climates
which began to emerge. Although these angiosperms did not develop shrub or tree like
morphologies, by the Cenomanian age they had radiated into a new habitat: disturbed riparian
areas. Ferns dominated open, dry and/or low-nutrient lands.
• Typical Jurassic vegetation, including conifers, cycads, and other gymnosperms, continued on into
the Early Cretaceous without significant changes. At the beginning of this period, conifer diversity
was fairly low in the higher latitudes of the Northern Hemisphere, but by the middle of this period,
species diversification was increasing exponentially.
• Ferns dominated open, dry and / or low-nutrient land. However, the up-and-coming angiosperms
took over cycad and cycadeoid habitats. High southern latitudes were not invaded by angiosperms
until the end of the Cretaceous.
• Swamps were dominated by conifers and angiosperm dicots .
29. The Cretaceous-Tertiary Extinction
• The most famous, if not the largest, of all mass extinctions marks the end of
the Cretaceous Period, 65 million years ago. As everyone knows, this was the
great extinction in which the dinosaurs died out. (Except for the birds, of
course.) The other lineages of "marine reptiles", such as the ichthyosaurs,
plesiosaurs, and mosasaurs, also were extinct by the end of the Cretaceous, as
did the flying pterosaurs -- although some, like the ichthyosaurs, were probably
extinct a little before the end of the Cretaceous. Many species of
foraminiferans went extinct at the end of the Cretaceous, as did the
ammonites.
• But many groups of organisms, such as flowering plants, gastropods and
pelecypods (snails and clams), amphibians, lizards and snakes, crocodilians,
and mammals "sailed through" the Cretaceous-Tertiary boundary, with few or
no apparent extinctions at all.
Fast Facts
-Numerous evolutionary radiations occurred during the Cretaceous
(144-65 million years ago)
- A major extinction occurred at the end of the period.
- 85% of all species died in the End-Cretaceous (K-T) extinction
Mass Extinctions
Several mass extinctions are recorded in the fossil record.
Paleontologists have been able to recognize patterns within and
between extinction events. Currently, there are five major extinction
patterns recognized. Steven M. Stanley, has outlined them in his book
entitled, Extinction
The End-Cretaceous (K-T) Extinction
30. Geological Setting
• Following the Permian mass extinction, life was abundant but there was a low diversity
of species. However, through the Triassic, Jurassic, and Cretaceous, major faunal
radiations resulted in a large number of new species and forms. New terrestrial fauna
that made their first appearance in the Triassic included the dinosaurs, mammals,
pterosaurs (flying reptiles), amphibians (including frogs and turtles). In addition, the
first birds appeared in the Jurassic. Among the terrestrial flora, the gymnosperms of
the Permian remained dominant until the evolution of the angiosperms (flowering
plants) in the Cretaceous.
• In the Cretaceous there was also major radiations occurring in several esablished
grounps including the the marine reptiles, rudist bivalves, ammonoids, belemnoids, and
scleractinian corals. Bivalves, and brachiopods. Marine groups that were present but
did not undergo major evolutionary expansion in the period included the gastropods,
bryozoans, crinoids, sea urchins, and sponges.
• Species Affected
• During the End-Cretaceous (K-T) extinction (65 million years ago) eighty-five percent of all species
disappeared, making it the second largest mass extinction event in geological history.
• This mass mass extinction, extinction event has generated considerable public interest, primarily
because of its role in the demise of the dinosaurs. Although dinosaurs were among the unfortunate
victims to perish in the K-T extinction, several other terrestrial and marine biotic groups were also
severely affected or eliminated in the crisis. Among those that perished were the pterosaurs,
belemnoids, many species of plants (except amongst the ferns and seed-producing plants),
ammonoids, marine reptiles, and rudist bivalves
• Organisms which were severly affected included planktic foraminifera, calcareous nannoplankton,
diatoms, dinoflagellates, brachiopods, molluscs, echinoids, and fish.
• Remarkably, most mammals, birds, turtles, crocodiles, lizards, snakes, and amphibians were
primarily unaffected by the End-Cretaceous mass extinction
31. Extinction Processes
• Extinction strikes in both the land and the sea.
• On the land, while animals suffer repeatedly, plants tend to
be highly resistant to mass extinctions.
• Preferential disappearance of tropical forms of life during
mass extinctions.
• Tendency of certain groups of animals to experience them
repeatedly (for example, trilobites and ammonoids).
• Alleged equal spacing, or periodicity in geological time
(occurring about every 26 million years.
• These similarities between distinct extinction
occurrences aid paleontologists in determining the agents
the agents that perpetuated the disappearances of species
in each extinction event. Such agents are currently divided
into two types:
• Catastrophic Agents- such as meteorite impacts and comet
showers,
• Earth Agents- such as volcanism, glaciation, variations in
sea level, global climatic changes, and changes in ocean
levels of oxygen or salinity
•
Although these agents can explain mass extinction, the
causes of mass extinction events remains relatively
32. 1- On the land, the Dinosaures were the primary victims of
the terminal crisis.
2- In the seas . Ammonoides, which had flourished with
only temporary set beach through Mesozoic time
and huge Swimming Reptiles failed to make the transition
into the Cenozoic.
3- The Reef building rudists also died out along with
certain other groups of bivalve.
4- Calcareous nannoplanktonand planktonic foraminifera
suffered heavy losses , but they recovered during the
Cenozoic.
5- Many taxononmic groups declined before the end of the
Cretaceous period, but other taxa died out abruptly right at
the end.
6- Extinction was heaviest in tropical regions and another
important group of Mesozoic bivalves the Inoceramids also
decline and perhaps disappeared.
7- Rudists reef that formed within 1 or 2 millions years of
the end of the Maastrichtian age . the final age of the
Cretaceous period were weakly developed and the number
of species was depleted.
Nature of the terminal Cretaceous:
33. 1- Early in late Cretaceous time, about 65 million years ago, a
moderately severe extinction eliminated many species in the
marine realm.
2- During the past few years, this biotic crisis , which brough the
Mesozoic
Era to close, has been attracted special Attention because of
intriguing suggestion that the cause was the impact on earth of
large bolide(meteorite or comet).
3- The primary evidence for such an event is the presence of so-
called Irridium anomaly at the Cretaceous – Paleogene boundary in
many areas of the world (Irridium is an element that is generally
very rare in the earth's crust). But it is abundant in stony
meteorites
4- A meteorite or Comet, about 10 km, in diameter, exploding on
impact cloud have released the total amount of excessive iridium
observed in the rock record .
5- The biotic consequence of such colloision are difficult to
predict.
6- On likely, would be that a huge volume of dust and smoke would
be thrown up into the atmosphere to circle the earth
7- Blocking out a large percentage of sunlight, this global cloud
CRETACEOUS MASS EXTINCTION
34. Speculated Causes of the End-Cretaceous
Extinction• The End-Cretaceous mass extinction has generated considerable
public interest in recent years, in response to the controversial
debates in the scientific community over its cause.
• The more prominent of these new hypoteses invoke extra-
terrestrial forces, such as meteorite impacts or comet showers as
the causative extinction agent.
• Older hypotheses cite earthly mechanisms such as volcanism or
glaciation as the primary agent behind this mass extinction.
The K-T Boundary
• Evidence for catastrophism at the Cretaceous-Tertiary boundary is found in
a layer of sediment which was deposited at the same time that the
extinction occurred.
• This layer contains unusually high concentrations of Iridium, found only in
the earth's mantle, and in extra-terrestrial meteors and comets.
• This layer has been found found in both marine and terrestrial sediments, at
numerous boundary sites around the world.
35. Meteorite Impact
• Some paleontologists believe that the widespread
distribution of this Iridium layer could have only been
caused by meteorite impact. Further, these researchers
cite the abundance of small droplets of basalt, called
spherules, in the boundary layer as evidence that basalt
from the earth's crust that were melted and flung into the
air upon impact.
• The presence of shocked quartz - tiny grains of quartz that
show features diagnostic of the high pressure of impact -
found in the boundary layer provides additional evidence of
an extra- terrestrial impact at the Cretaceous-Tertiary
boundary layer.
• Recent research suggests that the impact site may have
been in the Yucatan Peninsula of Mexico.
36. Volcanic Eruptions
• The high concentrations of Iridium in the boundary layer has also
been attributed to another source, the mantle of the earth.
• It has been speculated by some scientists that the Iridium layer
may be the result of a massive volcanic eruption, as evidenced by
the Deccan Traps - extensive volcanic deposits laid down at the
Cretaceous-Tertiary boundary - of India and Pakistan.
• These lava flows came about when India moved over a "hot spot"
in the Indian Ocean, producing flows that exceeded one hundred
thousand square kilometers in area and one hundred and fifty
meters in thickness.
• Such flows would have produced enormous amounts of ash,
altering global climatic conditions and changing ocean chemistry.
Evidence that volcanism was a primary extinction agent at this
boundary is also relatively strong.
• In addition, and the presence of spherules and shocked quartz
worldwide in the boundary layer may also have been the result of
such explosive volcanism.
• Thus at present, both the volcanic and meteorite impact
hypotheses are both viable mechanisms for producing the
Cretaceous mass extinction, although the latter is more popular
37. Cretaceous: ClimateClimate warm. In the early Cretaceous time , the
temperature was generally below normal. Similar lower
temperature were prevalent in many other parts of the
world as shown by the distribution of plants and animal
fossils;
In the upper Cretaceous beds , abundant remains of land
plants now restricted to temperates or sub-tropical region
are recorded.
By the close of the Cretaceous, the general temperature
dropped because the continent stood higher than usual due
to the great mountain formed at the time of the Rocky
Mountains- Great Alpine Revolution.
Cretaceous: Orogeny
• Towards the close of the Cretaceous , there was vigerous crustal
deformation including both folding of strata.This great crustal
disturbance has been called ‘ Rocky Mountain” or “Laramide”
Revolution.
• A number of great , elongate, dome –like anticline with cores of
Pre-Cambrian granite were found. The Rocky Mountain orogeny “”
Great Alpine Tectonic disturbance of Europe “ began well before
the close of Cretaceous and continued with more or less intensity
into the Early Tertiary